The mass range of neutron stars is not large, ranging from more than 1.44 times the mass of the sun (the maximum mass limit of white dwarfs, called the Chandrasekhar limit) to less than 3.2 times the mass of the sun (the maximum mass limit of neutron stars, called the Oppenheimer limit)

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West Virginia University researchers helped discover the most massive neutron star yet, a breakthrough discovered through the Green Bank Telescope in Pocahontas County.

The neutron star, named J0746620, is a pulsar with a mass 2.17 times that of the sun, forming a sphere with a diameter of only 20-30 kilometers (about 15 miles).

This measurement approaches the limit for a single object to become so massive and dense without crushing itself into a black hole.

The neutron star was detected about 4,600 light-years away from Earth.

The findings, from the National Science Foundation-funded NANOGrav Center for Physics Frontiers, were published in the journal Nature Astronomy.

Authors of the paper include Duncan Lorimer, professor of astronomy and associate dean for research in the Eberly College of Arts and Sciences; Eberly Distinguished Professor of Physics and Astronomy Maura McLaughlin; systems administrator for physics and astronomy

Nate Garver-Daniels; postdocs and former students Harsha Blumer, Paul Brooker, Pete Gentile, Megan Jones and Michael Lin.

The discovery is one of many serendipitous results that have emerged from routine observations searching for gravitational waves.

At the Green Bank Telescope, researchers are trying to detect gravitational waves from pulsars. To do this, they need to observe a large number of millisecond pulsars, which are also rapidly rotating neutron stars.

This discovery is not a gravitational wave detection paper, but one of many important results resulting from the observation.

Pulsar mass is measured through a phenomenon known as Shapiro delay.

Essentially, according to Einstein's theory of general relativity, the gravitational pull from a white dwarf companion warps the space around it.

This allows the pulses from the pulsar to travel a little further as they travel through the distorted space-time around the white dwarf.

This delay will tell scientists the mass of the white dwarf, which in turn provides a measure of the neutron star's mass.

Neutron stars are the compressed remnants of massive stars that went supernova. They are created when a giant star dies in a supernova and its core collapses, causing protons and electrons to melt into each other to form neutrons.

While astronomers and physicists have been studying these objects for decades, many mysteries remain about their internal properties: Do smashing neutrons become "superfluid" and flow freely?

Will they disintegrate into a soup of subatomic quarks or other exotic particles?

What is the tipping point when gravity overcomes matter and a black hole forms?

These neutron stars are very strange. A really important question is, how big is the largest neutron star that can be made?

Effects on very exotic materials that we just can't create in laboratories here on Earth.

Pulsars get their name because they emit twin beams of radio waves from their magnetic poles.

These beams sweep across space in a beacon-like fashion, some rotating hundreds of times per second.

Because pulsars spin with such incredible speed and regularity, astronomers can use them as the cosmic equivalent of atomic clocks.

This precise timing helps astronomers study the nature of space-time, measure mass, and improve understanding of general relativity.